Solution : https://service.sap.com/sap/support/notes/549762 (SAP Service marketplace login required)
Key words : 
ps master record transaction, prerequisites program error, attached advance correction, wbs elements, terms cj02, cj20n reason, solution implement, transferred, note 495726, prerequisite
Related Notes : 
       
| 1379903 | |
| 639596 | Status changes of WBS elements are not saved | 
| 495726 | Overall plan incrct if WBS elemnt w/ deletn flag in project |